LONDON — The Supreme Court has ruled that employment tribunal fees are illegal, in a victory for the trade union Unison who brought the appeal against the government.

The fees had led to a 79% reduction in cases going to tribunals over three years.

The court said: “The Fees Order is unlawful under both domestic and EU law because it has the effect of preventing access to justice. Since it had that effect as soon as it was made, it was therefore unlawful and must be quashed.”

The “Fees Order”, which meant claimants to employment tribunals had to pay a fee before a case was heard before a tribunal, was introduced under former justice secretary Chris Grayling in 2013.

Under the system claimants could be charged £390 or £1200 to have their case heard in an employment tribunal, even if it concerned sums of money that were less than that.

“Even where fees are affordable, they prevent access to justice where they render it futile or irrational to bring a claim,” the court ruled.

“The constitutional right of access to the courts is inherent in the rule of law: it is needed to ensure that the laws created by Parliament and the courts are applied and enforced,” the court argued.

Unison General Secretary Dave Prentis said: “Today’s result should bring to an end the cruel employment tribunal fees regime, and ensure that no-one else is ever forced to pay crippling fees just to access basic justice.”

Women were also unfairly targeted by employment tribunal fees, the court found, a they said tribunal fees are “indirectly discriminatory under the Equality Act 2010,” as women are more likely to pay higher fees.

Jonathan Bartley, co-leader of the Green Party said: “Employment tribunal fees block workers from accessing justice. The Government must scrap them in light of the Supreme Court’s judgement. This ruling is a victory for access to justice and common sense.”

The verdict suggests that the Supreme Court is more willing to challenge the government and limit its powers when it attempts to go beyond the sovereignty of parliament with secondary legislation, something that could impact the EU withdrawal bill’s progress.